Many of today's modern computing systems are provided as data centers where relatively large quantities of equipment modules are implemented for use as storage systems, telecommunications systems, and computationally intensive processing systems. To house such equipment modules, computing racks have been developed. Electrical power for these computing devices is typically provided by a power distribution unit in which electrical power from only one or a few sources can be distributed among the multiple equipment modules. In many cases, a computing rack may be configured with multiple power distribution units for various reasons, such as redundancy, power sharing, computing rack wiring organization, and the like. It is quite difficult to determine which power distribution unit is supplying electrical power to each equipment module due to the numerous equipment modules in a rack and the associated cabling.